Truly random numbers are utilized in many branches of science and technology, from fundamental research in quantum mechanics to practical applications such as cryptography, authentication, simulation, and gambling. Conventional quantum random number generators (QRNG) are used to yield random numbers for such applications, and are based on the physics of quantum mechanics which hold that a quantum state is truly random or an unreproducible source of true randomness.
Among various QRNG implementations, schemes based on photonic technology have drawn a lot of attention for high rates, low cost, and the potential of chip-size integration. Nevertheless, there are still practical challenges in these conventional systems. Specifically, conventional QRNG implementations have yielded nonuniform distributions that can lead to predictability, which is considered undesirable for efforts to yield true randomness.
Some conventional RNGs rely on very low photon fluences, and therefore require very low detector electrical noise. Other conventional RNGs may rely on current and voltage control of the local oscillator to adjust the measured noise in order to minimize classical noise sources. Conventional QRNGs that measure vacuum noise also rely on lasers to make the LO, which is costly and requires high power to drive the laser source.